Azo dyes, a process for their preparation and their use in the dyeing or printing of hydrophobic fiber materials

ABSTRACT

The present invention relates to an azo dye of formula (1), wherein R 1  is the radical of a diazo component of the benzene, naphthalene, diphenyl, azobenzene, thiophene, benzothiazole, thiadiazole, indazole, benzatriazole, pyrazole, anthraquinone, naphtholic acid imide, chromone, phthalimide or diphenylene oxide series, R 2  is an unsubstitued or substitued aryl radical or an unsubstituted or substituted aralkyl radical and R 3  is an unsubstituted or substituted aryl radical or an unsubstituted or substituted aralkyl radical, with the proviso that one of the substituents R 2  and R 3  is an unsubstituted or substituted aryl radical and the other is an unsubstituted or substituted aralkyl radical, 2-hydroxy-2-phenylethyl being expected as a substituted aralkyl radical, to mixtures comprising at least two structually different azo dyes of formula (1) and to the use of those azo dyes and dye mixtures in the dyeing or printing of semi-synthetic or synthetic hydrophobic fibre materials.

The present invention relates to azo dyes, to their preparation and totheir use in the dyeing or printing of semi-synthetic or synthetichydrophobic fibre materials.

Azo dyes and their use in the dyeing of semi-synthetic or synthetichydrophobic fibre materials are known. It has been shown, however, thatsuch dyes do not always fully satisfy the highest demands, especially inrespect of high temperature light fastness and/or colour strength. Thereis therefore a need for new dyes that yield tinctorially strong,alkali-stable dyeings or prints having high temperature light fastnessand that exhibit good allround properties.

It has now been found, surprisingly, that the azo dyes according to theinvention meet the criteria given above to a considerable degree.

The present invention accordingly relates to an azo dye of formula

wherein

-   R₁ is the radical of a diazo component of the benzene, naphthalene,    diphenyl, azobenzene, thiophene, benzothiazole, benzisothiazole,    thiadiazole, indazole, benzotriazole, pyrazole, anthraquinone,    naphtholic acid imide, chromone, phthalimide or diphenylene oxide    series,-   R₂ is an unsubstituted or substituted aryl radical or an    unsubstituted or substituted aralkyl radical and-   R₃ is an unsubstituted or substituted aryl radical or an    unsubstituted or substituted aralkyl radical,    with the proviso that one of the substituents R₂ and R₃ is an    unsubstituted or substituted aryl radical and the other is an    unsubstituted or substituted aralkyl radical,    2-hydroxy-2-phenyl-ethyl being excepted as a substituted aralkyl    radical.

Of the substituents R₁, the radicals of a diazo component of thebenzene, naphthalene and thiophene series are preferred.

Especially preferred as R₁ is the radical of a diazo component of thebenzene series. The aryl radicals denoted by R₂ and R₃ may be mono- orpoly-substituted, especially mono- to tri-substituted, e.g. byC₁–C₄alkyl, C₁–C₄alkoxy or halogen.

Preferably, the aryl radicals denoted by R₂ and R₃ are unsubstituted orsubstituted by methyl, methoxy, chlorine or fluorine.

The aryl radicals denoted by R₂ and R₃ are especially substituted bymethyl in the ortho-position and, more especially, the meta-position tothe amino group.

The radicals R₂ and R₃ are very especially unsubstituted.

A preferred aryl radical for R₂ and R₃ is phenyl.

C₁–C₄Alkyl as a substituent of R₂ and/or R₃ may be, for example, methyl,ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.

C₁–C₄Alkoxy as a substituent of R₂ and/or R₃ is e.g. methoxy, ethoxy,propoxy or butoxy.

A preferred aralkyl radical for R₂ and R₃ is phenyl-C₁–C₄alkyl,especially 2-phenylethyl or benzyl.

The phenyl radical in phenyl-C₁–C₄alkyl can itself be mono- orpoly-substituted by the substituents indicated above for “arylradicals”.

Preferably, the phenyl radical in phenyl-C₁–C₄alkyl does not itselfcarry substituents.

Halogen as a substituent of R₂ and/or R₃ is bromine, fluorine orespecially chlorine.

The azo dyes of the following formulae are important:

The present invention relates also to dye mixtures comprising at leasttwo structurally different azo dyes of formula (1).

Preference is given to dye mixtures comprising two structurallydifferent azo dyes of formula (1).

Special preference is given to dye mixtures comprising the azo dyes offormulae (2) and (3), (4) and (5), (6) and (7), and (8) and (9).

The amount of the individual dyes in the dye mixtures according to theinvention may vary within wide limits from e.g. 95:5 to 5:95 parts byweight, especially from 70:30 to 30:70 parts by weight, more especiallyfrom 55:45 to 45:55 parts by weight, of the individual dyes in a dyemixture comprising two azo dyes according to the invention.

Very special preference is given to dye mixtures comprising thefollowing structurally different azo dyes of formula (1):

-   A. azo dyes of formulae (2), (3), (4) and (5), and-   B. azo dyes of formulae (6), (7), (8) and (9).

The amounts of the azo dyes in dye mixture A. may likewise vary withinwide limits, preference being given to dye mixtures in which the sum ofthe azo dyes of formulae (2) and (3) and the sum of the azo dyes offormulae (4) and (5) varies in a ratio by weight between 95:5 and 5:95,especially between 70:30 and 30:70, more especially between 55:45 and45:55, the definitions and preferences given above for the dye mixturecomprising two azo dyes according to the invention applying also to theratio of the azo dyes of formulae (2) and (3), and (4) and (5).

The amounts of the azo dyes in dye mixture B. may likewise vary withinwide limits, preference being given to dye mixtures in which the sum ofthe azo dyes of formulae (6) and (7) and the sum of the azo dyes offormulae (8) and (9) varies in a ratio by weight between 95:5 and 5:95,especially between 70:30 and 30:70, more especially between 55:45 and45:55, the definitions and preferences given above for the dye mixturecomprising two azo dyes according to the invention applying also to theratio of the azo dyes of formulae (6) and (7), and (8) and (9).

The present invention relates also to the process for the preparation ofthe azo dyes of formula (1) according to the invention.

The dyes are prepared, for example, as follows: a compound of formulaR₁—NH₂  (50)is diazotised in accordance with a customary procedure and then coupledto a coupling component of formula

wherein R₁, R₂ and R₃ are as defined above for formula (1).

The diazotisation of the compound of formula (50) is carried out in amanner known per se, for example with sodium nitrite in an acidic, e.g.hydrochloric-acid-containing or sulfuric-acid-containing, aqueousmedium. The diazotisation may, however, also be carried out using otherdiazotisation agents, e.g. using nitrosylsulfuric acid. In thediazotisation, an additional acid may be present in the reaction medium,e.g. phosphoric acid, sulfuric acid, acetic acid, propionic acid orhydrochloric acid or a mixture of such acids, e.g. a mixture ofpropionic acid and acetic acid. The diazotisation is advantageouslycarried out at temperatures of from −10 to 30° C., for example from −10°C. to room temperature.

The coupling of the diazotised compound of formula (50) to the couplingcomponent of formula (51) is likewise effected in known manner, forexample in an acidic, aqueous or aqueous-organic medium, advantageouslyat temperatures of from −10 to 30° C., especially below 10° C. Examplesof acids used are hydrochloric acid, acetic acid, propionic acid,sulfuric acid and phosphoric acid.

The compounds of formula (50) are known or can be prepared in a mannerknown per se. The coupling components of formula (51) are also known orcan be prepared in a manner known per se.

A dye mixture comprising two structurally different azo dyes of formula(1) can be pr pared, for example, as follows: a compound of formulaR₁—NH₂  (50)is diazotised in accordanc with a customary procedure and then coupledto a coupling component mixture comprising the compounds of formulae

wherein R₁, R₂ and R₃ are as defined above for formula (1) and R₄ hasthe same meanings as R₃ independently of R₃ and n and m are the numbers1, 2 or 3.

The above coupling component mixture can be prepared, for example, asfollows: a compound of formula

is reacted first with a compound of formula

and then with a compound of formula

wherein R₃, R₄, n and m are as defined above.

From the resulting coupling component mixture, the individual couplingcomponent(s) of formula (51) or formulae (51a) and (51b) can be obtainedby subsequent chromatographic separation.

The dye mixtures comprising four structurally different azo dyes offormula (1) can be prepared, for example, by simply mixing together twoof the two-component dye mixtures described above, e.g. a mixturecomprising the azo dyes of formulae (2) and (3) and a mixture comprisingthe azo dyes of formulae (4) and (5).

The azo dyes and dye mixtures according to the invention can be used inthe dyeing and printing of semi-synthetic and, especially, synthetichydrophobic fibre materials, more especially textile materials. Textilematerials composed of blends that contain such semi-synthetic and/orsynthetic hydrophobic textile materials can likewise be dyed or printedusing the azo dyes or dye mixtures according to the invention.

Semi-synthetic textile materials that come into consideration areespecially cellulose secondary acetate and cellulose triacetate.Synthetic hydrophobic textile materials consist especially of linear,aromatic polyesters, for example those of terephthalic acid and glycols,especially ethylene glycol, or condensation products of terephthalicacid and 1,4-bis(hydroxymethyl)cyclohexane; of polycarbonates, e.g.those of α,α-dimethyl-4,4-dihydroxy-diphenylmethane and phosgene, and offibres based on polyvinyl chloride and on polyamide.

The application of the azo dyes and dye mixtures according to theinvention to the textile materials is effected in accordance with knowndyeing procedures. For example, polyester fibre materials are dyed inthe exhaust process from an aqueous dispersion in the presence ofcustomary anionic or non-ionic dispersants and optionally customaryswelling agents (carriers) at temperatures of from 80 to 140° C.Cellulose secondary acetate is dyed preferably at about from 65 to 85°C. and cellulose triacetate at temperatures of up to 115° C.

The azo dyes and dye mixtures according to the invention will not colourwool and cotton present at the same time in the dyebath or will coloursuch materials only slightly (very good reservation), so that they canalso be used satisfactorily in the dyeing of polyester/wool andpolyester/cellulosic fibre blend fabrics.

The azo dyes and dye mixtures according to the invention are suitablefor dyeing in accordance with the thermosol process, in the exhaust andcontinuous process and for printing processes. The exhaust process ispreferred. The liquor ratio is dependent upon the nature of theapparatus, the substrate and the form of make-up. It may, however, beselected within a wide range, e.g. from 1:4 to 1:100, but is preferablyfrom 1:6 to 1:25.

The said textile material can be in a variety of processing forms, e.g.in the form of fibres, yarns or non-wovens, in the form of woven fabricsor knitted fabrics.

It is advantageous to convert the azo dyes and dye mixtures according tothe invention into a dye preparation prior to use. For this purpose, theazo dyes are ground so that their particle size is on average from 0.1to 10 microns. The grinding can be carried out in the presence ofdispersants. For example, the dried azo dye is ground with a dispersantor is kneaded in paste form with a dispersant and then dried in vacuo orby atomisation. The preparations so obtained can be used, after theaddition of water, to prepare printing pastes and dyebaths.

For printing, the customary thickeners will be used, e.g. modified orunmodified natural products, for example alginates, British gum, gumarabic, crystal gum, locust bean flour, tragacanth,carboxymethylcellulose, hydroxyethylcellulose, starch or syntheticproducts, for example polyacrylamides, polyacrylic acid or copolymersthereof, or polyvinyl alcohols.

The azo dyes and dye mixtures according to the invention impart to thementioned materials, especially to polyester material, level colourshades having very good in-use fastness properties, such as, especially,good fastness to light, more especially very good high temperature lightfastness, fastness to thermofixing, to pleating, to chlorine and towetting, such as fastness to water, perspiration and washing; thefinished dyeings are also distinguished by good fastness to rubbing.

The azo dyes and dye mixtures according to the invention can also beused satisfactorily in the preparation of mixed shades together withother dyes.

The azo dyes and dye mixtur s according to the invention can be usedespecially as a suitable component in a trichromatic dyeing or printingtechnique.

In the process for trichromatic dyeing of semi-synthetic or synthetichydrophobic fibre materials there is used at least one red-dyeing azodye of formula

wherein R₁ is the radical of a diazo component of the benzene,naphthalene, diphenyl, azobenzene, thiophene, benzothiazole,benzisothiazole, thiadiazole, indazole, benzotriazole, pyrazole,anthraquinone, naphtholic acid imide, chromone, phthalimide ordiphenylene oxide series, R₂ is an unsubstituted or substituted arylradical or an unsubstituted or substituted aralkyl radical and R₃ is anunsubstituted or substituted aryl radical or an unsubstituted orsubstituted aralkyl radical, with the proviso that one of thesubstituents R₂ and R₃ is an unsubstituted or substituted aryl radicaland the other is an unsubstituted or substituted aralkyl radical,2-hydroxy-2-phenylethyl being excepted as a substituted aralkyl radical,optionally in combination with further red dyes, e.g. C.I. Disperse Red086, C.I. Disperse Red 279, Dianix Rot HF-LS (Dystar) or Palanil Rot FFB(BASF),at least one blue-dyeing dye of formula

and at least one yellow-dyeing dye of formula

The dyes of formulae (10) to (18) are known or can be preparedanalogously to known compounds in accordance with procedures known perse.

The definitions and preferences given above apply also to the red-dyeingazo dye of formula (1).

Trichromatic dyeing is the additive colour mixing of suitably selectedyellow- or orange-dyeing, red-dyeing and blue-dyeing dyes with which anydesired shade of the visible colour spectrum can be achieved by anappropriate choice of the relative proportions of the dye components.

In a preferred embodiment of the trichromatic process according to theinvention, a dye mixture comprising the red-dyeing azo dyes of formulae(2), (3), (4) and (5) together with the blue-dyeing dyes of formulae(10) and (11) and the yellow-dyeing dye of formula (12) is used.

In a further preferred embodiment of the trichomatic process accordingto the invention, a dye mixture comprising the red-dyeing azo dyes offormula (6), (7), (8) and (9) together with the blue-dyeing dyes offormulae (10) and (11) and the yellow-dyeing dye of formula (12) isused.

The present invention relates also to a trichromatic mixture comprisingat least one red-dyeing azo dye of formula

wherein R₁ is the radical of a diazo component of the benzene,naphthalene, diphenyl, azobenzene, thiophene, benzothiazole,benzisothiazole, thiadiazole, indazole, benzotriazole, pyrazole,anthraquinone, naphtholic acid imide, chromone, phthalimide ordiphenylene oxide series, R₂ is an unsubstituted or substituted arylradical or an unsubstituted or substituted aralkyl radical and R₃ is anunsubstituted or substituted aryl radical or an unsubstituted orsubstituted aralkyl radical, with the proviso that one of thesubstituents R₂ and R₃ is an unsubstituted or substituted aryl radicaland the other is an unsubstituted or substituted aralkyl radical,2-hydroxy-2-phenylethyl being excepted as a substituted aralkyl radical,at least one blue-dyeing dye of formulae (10) to (13) and at least oneyellow-dyeing dye of formulae (14) to (18).

The definitions and preferences given above apply also to the red-dyeingazo dye of formula (1).

The azo dyes and dye mixtures according to the invention are also verysuitable for dyeing hydrophobic textile material from supercritical CO₂.

The present invention relates also to the above-mentioned use of the azodyes and dye mixtures according to the invention as well as to a processfor the dyeing or printing of semi-synthetic or synthetic hydrophobicfibre material, especially textile material, which process comprisesapplying the azo dyes or dye mixtures according to the invention to thesaid material or incorporating them into that material. The saidhydrophobic fibre material is preferably textile polyester material.Further substrates that can be treated by the process according to theinvention and also preferred process conditions can be found above inthe detailed description of the use of the azo dyes and dye mixturesaccording to the invention. The invention relates also to hydrophobicfibre material, especially polyester textile material, dyed or printedby the said process.

The azo dyes and dye mixtures according to the invention are alsosuitable for modern reproduction processes, e.g. thermotransferprinting.

The following Examples serve to illustrate the invention. In theExamples, unless otherwise indicated, parts are parts by weight andpercentages are percent by weight. The temperatures are given in degreesCelsius. The relationship between parts by weight and parts by volume isthe same as that between grams and cubic centimetres.

EXAMPLE 1

A. In a Laboratory Reaction Apparatus,

with stirring and with cooling at a temperature of from 20 to 30° C.,27.80 g of 2-amino-5-nitro-benzonitrile are introduced into 40.00 g of a97% sulfuric acid and stirring is carried out for 30 minutes. A further10.00 g of a 97% sulfuric acid are then added to the resultingsuspension, with stirring, and the reaction mass is stirred for afurther 30 minutes and cooled to about from 5 to 15° C. 47.70 g of a 40%nitrosylsulfuric acid are then added dropwise and the resulting solutionis then stirred for 2 hours at from 10 to 20° C.

B. In a Laboratory Reaction Apparatus,

76.00 g of powdered 2,6-dichloro-3-cyano-4-methylpyridine are suspendedin 250.00 ml of triethylamine and the suspension is heated to from 50 to55° C. At that temperature, 49.00 g of phenethylamine are added dropwiseand the mixture is stirred at 60° C. for 12 hours. The temperature isthen increased to about from 80 to 90° C., and the triethylamine isseparated off by distillation for about 10 hours. 100.00 ml of anilineare then added dropwise to the resulting solution and the solution isstirred at 150° C. for 12 hours. 450.00 ml of a 4N HCl are then addedand the reaction mass is poured into 150.00 g of ice and stirred forabout 3.5 hours, filtered with suction, washed with 6.00 litres of waterand dried.

C. In a Laboratory Reaction Apparatus,

63.30 g of the coupling component mixtur prepared under B. areintroduced into a mixture of 250.00 ml of a 2N HCl and 200.00 ml ofwater. The resulting suspension is stirred for 1 hour, then filteredwith suction and washed with water and the resulting filter cake isintroduced into 200.00 ml of a 80% acetic acid.

100.00 ml of ethyl alcohol are added to the resulting suspension; themixture is cooled to about 0° C. and the diazo solution prepared underA. is added dropwise in the course of 30 minutes at a temperature of <8°C.

The resulting very viscous reaction mass is diluted with 150.00 ml ofwater and stirred for 3 hours at from 5 to 10° C.

The precipitated reaction product is then filtered off with suction,washed with water and dried.

76.60 g of a dye mixture consisting of the azo dyes of formulae

are obtained, which dyes polyester in red shades.

If required, the individual azo dyes of formulae (8) and (9) can beisolated by subsequent chromatographic separation.

Analogously to Example 1 it is possible to prepare the azo dyes listedin Tables 1 and 2, which likewise dye polyester in orange toreddish-violet shades:

TABLE 1

R₁ R₂ R₃

TABLE 2

R₁ R₂ R₃

EXAMPLE 2

Using a liquor ratio of 1:20, 100 g of polyester fabric are immersed atroom temperature in a liquor containing

-   0.07 g of a dye mixture comprising the azo dyes of formulae (2),    (3), (4) and (5) in a ratio of 1:1:1:1,-   0.058 g of a dye mixture comprising the dyes of formulae (10)    and (11) in a ratio of 1:1, 0.57 g of a dye of formula (12),-   1 g/l of ammonium sulfate and-   0.5 g/l of a commercially available levelling agent,    the liquor having been adjusted to a pH of 4.5 to 5 with 80% formic    acid. The liquor is then heated first to 60° C. at a heating rate of    3° C./minute and then to 130° C. at a heating rate of 2° C./minute.

Dyeing is carried out at 130° C. for 60 minutes. The liquor is thencooled to 40° C. and the dyed polyester fabric is washed with water andcleaned reductively for 20 minutes at 70–80° C. in a bath containing 5ml/l of 30% sodium hydroxide solution, 2 g/l of 85% sodium dithionitesolution and 1 g/l of a commercially available detergent. The finisheddyeing is then washed with water and dried.

A tinctorially strong violet dyeing having good allround properties,especially excellent high temperature light fastness properties, isobtained.

1. An azo dye of formula

wherein R₁ is 2-trifluoromethyl-4-nitrophenyl, 2-cyano-4-nitrophenyl,2-cyano-4-nitro-6-bromophenyl, 2-trifluoromethyl-4-chlorophenyl,3,5-dicyano-4-methyl-2-thienyl or 2-cyano-4-nitro-1-naphthyl, R₂ isphenyl, benzyl or 2-phenylethyl and R₃ is phenyl, benzyl or2-phenylethyl, with the proviso that either R₂ is phenyl and R₃ isbenzyl or 2-phenylethyl or R₃ is phenyl and R₂ is benzyl or2-phenylethyl.
 2. A process for the preparation of an azo dye of formula(1) according to claim 1, wherein a compound of formulaR₁—NH₂  (50) is diazotised in accordance with a customary procedure andthen coupled to a coupling component of formula

wherein R₁, R₂ and R₃ are as defined for formula (1).
 3. A process forthe dyeing or printing of semi-synthetic or synthetic hydrophobic fibrematerial, wherein an azo dye of formula (1) according to claim 1 isapplied to the said material or is incorporated into that material.
 4. Amethod of dyeing or printing of semi-synthetic or synthetic hydrophobicfibre materials comprising treating said materials with an azo dye offormula (1) according to claim
 1. 5. A semi-synthetic or synthetichydrophobic fibre material dyed or printed with a dye of formula (1)according to claim 1.